Bottom Line:
Some of fluoxetine effects were attributed to its capability of cAMP signaling pathway stimulation.In conclusion, data showed that fluoxetine alone and in the absence of serotonin acutely up-regulated Cx43 expression in astrocytes that can be assumed in molecular target therapy of MS patients.It seems that cAMP involvement in fluoxetine effects need more researches.

Introduction: Recent studies have shown that astrocytes play major roles in normal and disease condition of the central nervous system including multiple sclerosis (MS). Molecular target therapy studies in MS have revealed that connexin-43 (Cx43) and Aquaporin-4 (AQP4) contents of astrocytes undergo expression alteration. Fluoxetine had some effects in MS patients unrelated to its known antidepressant effects. Some of fluoxetine effects were attributed to its capability of cAMP signaling pathway stimulation. This study aimed to investigate possible acute effects of fluoxetine on Cx43 and AQP4 expression in astrocyte.

Methods: Astrocytoma cells were treated for 24 hours with fluoxetine (10 and 20 µg/ml) with or without adenyl cyclase (AC) and protein kinase A (PKA) inhibition. Cx43 expression at both mRNA and protein levels and AQP4 expression at mRNA level were evaluated.

Results: Acquired results showed that fluoxetine with and without AC and PKA inhibition resulted in Cx43 up-regulation both in mRNA and protein levels, whereas AQP4 expression have not changed.

Discussion: In conclusion, data showed that fluoxetine alone and in the absence of serotonin acutely up-regulated Cx43 expression in astrocytes that can be assumed in molecular target therapy of MS patients. It seems that cAMP involvement in fluoxetine effects need more researches.

Figure 0003: Expression of Cx43 protein in the 1321N1 cells. Cx43 protein levels were normalized to that of β-actin protein. Data are expressed as means ± S.E.M. Each immunoblotting was performed in duplicate to increase the reliability of the measurements. Lower Panels show representative immunoblots of Cx43 (43 kDa). C (un-treated), F (

Mentions:
Treatment of cells with 10 and 20 µg/ml of fluoxetine for 24 hours resulted in up-regulation of Cx43 both in mRNA (Fig. 2) and protein (Fig. 3) levels. These effects were not dose dependent. As our data revealed that in 40 µg/ml of fluoxetine complete cell death occurred. To evaluate the specificity of this finding cells pretreated for 45 minutes with SQ 22,536 (20 µg/ml) as an AC inhibitor, and H-89 (10 µg/ml), as PKA inhibitor, these pretreatments declined the fluoxetine effects on Cx43 expression, but not returned it to basal level. Suggesting that up-regulation of Cx43 seen in the presence of fluoxetine may have gone partially via cAMP-Epac and without PKA pathway.

Figure 0003: Expression of Cx43 protein in the 1321N1 cells. Cx43 protein levels were normalized to that of β-actin protein. Data are expressed as means ± S.E.M. Each immunoblotting was performed in duplicate to increase the reliability of the measurements. Lower Panels show representative immunoblots of Cx43 (43 kDa). C (un-treated), F (

Mentions:
Treatment of cells with 10 and 20 µg/ml of fluoxetine for 24 hours resulted in up-regulation of Cx43 both in mRNA (Fig. 2) and protein (Fig. 3) levels. These effects were not dose dependent. As our data revealed that in 40 µg/ml of fluoxetine complete cell death occurred. To evaluate the specificity of this finding cells pretreated for 45 minutes with SQ 22,536 (20 µg/ml) as an AC inhibitor, and H-89 (10 µg/ml), as PKA inhibitor, these pretreatments declined the fluoxetine effects on Cx43 expression, but not returned it to basal level. Suggesting that up-regulation of Cx43 seen in the presence of fluoxetine may have gone partially via cAMP-Epac and without PKA pathway.

Bottom Line:
Some of fluoxetine effects were attributed to its capability of cAMP signaling pathway stimulation.In conclusion, data showed that fluoxetine alone and in the absence of serotonin acutely up-regulated Cx43 expression in astrocytes that can be assumed in molecular target therapy of MS patients.It seems that cAMP involvement in fluoxetine effects need more researches.

Introduction: Recent studies have shown that astrocytes play major roles in normal and disease condition of the central nervous system including multiple sclerosis (MS). Molecular target therapy studies in MS have revealed that connexin-43 (Cx43) and Aquaporin-4 (AQP4) contents of astrocytes undergo expression alteration. Fluoxetine had some effects in MS patients unrelated to its known antidepressant effects. Some of fluoxetine effects were attributed to its capability of cAMP signaling pathway stimulation. This study aimed to investigate possible acute effects of fluoxetine on Cx43 and AQP4 expression in astrocyte.

Methods: Astrocytoma cells were treated for 24 hours with fluoxetine (10 and 20 µg/ml) with or without adenyl cyclase (AC) and protein kinase A (PKA) inhibition. Cx43 expression at both mRNA and protein levels and AQP4 expression at mRNA level were evaluated.

Results: Acquired results showed that fluoxetine with and without AC and PKA inhibition resulted in Cx43 up-regulation both in mRNA and protein levels, whereas AQP4 expression have not changed.

Discussion: In conclusion, data showed that fluoxetine alone and in the absence of serotonin acutely up-regulated Cx43 expression in astrocytes that can be assumed in molecular target therapy of MS patients. It seems that cAMP involvement in fluoxetine effects need more researches.